HUMAN ENGINE AND ITS FUEL.

Star (Christchurch), Issue 18418, 21 March 1928, Page 4

HUMAN ENGINE AND ITS FUEL.

SIMPLE RULES GIVEN ON DIET QUESTION. (Contributed by the Department of Health.) The uses of food are threefold, viz., to provide for growth, energy, and maintenance. An illustration from the now familiar motor-car will perhaps make these terms clear. A motor engine in course of construction requires the supply of viron, steel, copper, porcelain, insulation material, etc. In the same way the body during growth, must be provided with certain building materials. When the engine is completed fuel must be given in order that work may be done by it. The fuel does not enter as a constituent of the fabric, and corresponds to that part of our food which is used for the giving of energy. If the motor is kept at work certain parts require renewal and replacement. In the same way a fraction of the food is needed for maintenance of the human engine, or for repair of tissue waste resulting from the wear and and tear of ordinary life. Before leaving this analogy let us see if we can find any further resemblances between the human engine and the petrol motor. There are certain very necessary constituents of a dietary known as vitamins. If these are absent or in any way deficient, diseases such as scurvy, rickets, and beri-beri may result, going on in extreme cases to death. The vitamins have been likened to the spark which explodes the mixture in the cylinder of the motor. Water and salts again are indispensable for the proper working of the human machine, although they afford no energy. Their function may be likened perhaps to that of a lubricant. There is one great difference between the petrol motor and the human engine. The human body is doing some work all the time, even when resting or asleep. The muscles concerned with breathing and circulation of the blood, for instance, are never at rest. It is obvious then that full health and vigour cannot be maintained without proper food. Food falls into certain groups, each of which has its own special functions. We will now look at each of these in turn. It must be realized, however, that these groups occur in many natural foods in combination. Milk, tor instance, is an example of a food which is complete in itself, although it is not to be recommended as the sole food for adult use. Building and Repairing Foods. Proteins have been compared to building bricks. They build up broken down tissues, form new tissues, and can also be used as a source of heat and muscular energy. Examples of protein foods are :—From the animal kingdom: Meat, fish, eggs, cheese, and milk, and from the vegetable kingdom, wheat, peas, beans, lentils, etc. Proteins are not of even value, those in milk, meat, and eggs being the best. Carbohydrates and fats are fuel foods, that is, they cannot be used to build up the tissues, but merely serve as a source of heat and muscular energy. For this reason carbohydrates and fats will not maintain life alone, but must always be used in combination with proteins. Carbohydrates include starchy foods, such as potatoes, rice, bread, cereals, etc., and sugars such as ordinary cane sugar, honey, sugar of fruits, etc. Examples of fats are butter, cream, fat of meat. olive oil, etc. Carbohydrates and fats are more or less interchangeable. Fats give more heat than carbohydrates, and for this reason we find a natural desire for more fat to be included in the diet during the winter months, and in the diet of people living in cold climates. Mineral Salts. —Mineral matter is essential for health. It is absolutely necessary in the blood, and is needed also to build up Strong bones and teeth. Minerals are found in varying amounts in many foods, but more particularly in milk, eggs, green vegetables, fresh fruits, and cereals made from whole grain (oatmeal, brown bread, etc). These foods are important constituents of the diet, particularly in the growing child. Water.—Water is most important. It regulates the temperature, aids digestion, and, indeed, is needed by the blood and every tissue of the body. It is also the vehicle for carrying off certain of the waste products of the body. Few people drink too much water, but may fail to drink enough. A glass in the morning, on rising, one before or at each meal, and another on going to bed is a good health rule. Ballast or Bulk. —So far we have been dealing with foods only from the point of view of growth, energy, and maintenance. Something should be said about the laxative quality of food. Often the diet does not contain enough bulky or indigestible fibrous substances to stimulate the muscular movement of the intestines, constipation being the result. This will be avoided by the free use of vegetables, especially green vegetables, coarse (brown breads), and fruits, which furnish the necessary ballast or bulk. The use of these articles of diet also serves the additional purpose of giving adequate work to teeth and jaws. Some Simple Rules.—Eat foods with a high protein content (meat, fish, fowl, and eggs), only once a day, in moderate amount. Have some green vege tables, some fruit, and some milk in your diet each day. Drink plenty of water.